Recently, a technique for forming a recording layer by layering multiple layers is widely used in optical recording mediums in order to further increase recording capacity. In a multilayer optical recording medium, in order to make a sufficient amount of light reach a recording layer that is arranged at the innermost side from the surface of the medium, recording layers, which can transmit laser light to be used for recording and reproducing, (hereinafter called “transmissive recording layers” as necessary), are used as recording layers that are arranged at upper sides of the innermost side layer.
As a material for the transmissive recording layer, a material containing an oxide of at least one metal selected from the group consisting of tungsten (W) and molybdenum (Mo) and containing an oxide of at least one metal selected from the group consisting of copper (Cu), manganese (Mn), nickel (Ni), and silver (Ag), is proposed (for example, refer to Patent Literature 1).